The embodiments described herein relate generally to electrical machines, and more particularly, to methods and systems for assembling stators of the electrical machines.
Certain electrical machines are sometimes referred to as brushless motors. Brushless motors include both brushless AC motors and brushless DC motors and are used in a wide variety of systems operating in a wide variety of industries. Motors commonly include a stator having a plurality of stacked laminations and a central bore for receiving a rotor and associated bearings. A pair of end frames or end bells can be coupled to opposite ends of the stator to facilitate supporting the rotor. Proper radial and axial alignment between the motor components is desired to facilitate providing free rotation of the rotor, preventing excessive eccentricity in an annular air gap between the rotor and the stator and preventing excessive axial rotor thrust.
Typically, the stator laminations are formed with longitudinal slots on the periphery of each lamination. In some manufacturing processes, a relatively large number of laminations may be stacked on a welding arbor to a desired height. Conventionally, the welding arbor can be configured to radially expand against the inner circumference of the stack such that the individual laminations will be concentrically aligned around the axis of rotation. A welding device may be utilized to produce welds at predetermined locations within the slots. As a result, the laminations will be connected together into a core body that can be handled as a unit.
An extended cleat may be inserted radially into each slot and over the welds such that the cleat may extend longitudinally beyond each end of the stator. After installation of the cleat, the stator may be insulated. After insulation of the stator, windings can be injected into the stator and coupled to each other. The stator may also be coated and saturated with a bonding varnish.
Since the cleats may extend longitudinally beyond the stator ends, the cleats may present a cutting hazard to workers further handling the stator. Accordingly some processes may further cut off the cleat ends after varnishing the stator. Cutting off the cleat ends, however, may form uneven surfaces on the stator ends such that the stator end faces may not be perpendicular to the bore. Accordingly, the stator end faces may present uneven mounting surfaces for the component that houses the rotor and bearings which may result in interference and/or misalignment of the rotor.